An aqueous extract prepared from
the aerial parts of Zinnia
grandiflora was found not to induce acute toxicity (LD50> 5g/kg, p.o.) in mice when tested by the Lorke method.
This
extract showed notable antinociceptive and anti-inflammatory actions
when evaluated by the formalin- (ED50 = 224.62 ± 38.17
mg/kg, p.o.) and the carrageenan-induced paw edema models in mice,
respectively. The organic-soluble fractions obtained by partitioning
the infusion with CH2Cl2 and EtOAc were also
active in the formalin test. The most important antinociceptive effect
was observed with the CH2Cl2 fraction; extensive
fractionation of the latter yielded three new elemanolides, namely,
zinagranolides D–F (1–3),
which were characterized structurally by spectroscopic means. The
structure of compound 2 was established unequivocally
by an X-ray crystallographic analysis. This compound exerted a significant
antinociceptive effect in the formalin assay, better than that of
diclofenac used as a positive control.
Anxiolytic- and antidepressant-like T. parthenium effects result, at least part from the involvement of the GABAergic system. Our results support the use of Tanacetum parthenium in traditional medicine and suggest its therapeutic potential in the comorbid anxiety and depression.
Ceftriaxone (CFX) is a β‐lactam antibiotic with analgesic properties. However, its role in the formalin‐induced nociception remains unknown. The purpose of this study was to investigate the antinociceptive effect of CFX in the 1% formalin test in rats. Formalin induced a typical nociceptive response (flinching behavior) of two phases. Local peripheral pretreatment (20 min) with CFX (400–800 μg/paw) slightly attenuated the flinching behavior in phase 2, but not phase 1. Acute intraperitoneal pretreatment (20 min) also reduced phase 2 of the formalin test. In both cases, CFX induced a dose‐dependent antinociception. We also tested the effect of CFX 1 day after its administration and in two schedules of repeated administration. One‐day pretreatment with CFX (50–400 mg/kg, ip) induced a dose‐dependent antinociceptive effect in formalin‐treated rats. Repeated administration (daily during 3 or 7 days) with CFX (50–400 mg/kg, ip) diminished formalin‐induced nociception. Results suggest that local or systemic as well as single or repeated administration of CFX reduces formalin‐induced nociception.
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